Random Question About Flashing Lights

If you're not doing anything wrong, and there's nothing wrong with your truck, then it may be a way to alert you that they're passing. I live in New England and haven't noticed it (as a four-wheeler), but when I visited Delhi a few years ago, where everyone drives--well, there's no sugarcoating it, terribly--my cab drivers would ALWAYS flash their lights when passing trucks. They would semi-auto press the beams as fast as they could like they were playing a video game. I asked one driver why he did that and he said so the truck knew he was passing.

Yeah. I think that might be it. In my simulators, I usually flash over trucks who pass me, and I press that button as quickly as possible, like it's a video game (well, it is :P).